By Jeff Glucker
Steve Magnante is a junkyard and old-car savant. He knows his stuff and he’s also good at explaining all the interesting bits about a wide range of classic cars. In a new video posted to his YouTube channel, Steve is tearing down an old 440 for one of his project cars. And he pulls the head off which is the perfect time to show you the difference between a Hemi and a Wedge.
Way back in the early 1950s, the Moper meatiness was made possible with the Hemi. Soon though, the Max Wedge came along and was cranking out serious power. The Hemi love came back around though pretty quickly, and for good reason. The Max Wedge was a drag-strip dominator but also a bit too aggressive for the street, especially compared to the Hemis.
Additionally, the Hemis heads as shown in the video above allow for larger valves and also feature better airflow. You can see the angled valves and springs on the Hemi. So you’re going to have a different rocket setup as well.
Steve does a great job walking you through both versions in the clip above.
I think this video is a bit late; anyone who doesn’t know the difference between a 440 wedge head and a 426 hemi head is going to be too late to find the hemi in a junkyard anyway (and the 440 is going to be really scarce except for maybe in a motorhome).
But I didn’t realize Steve Mags had a Youtube channel. Better yet, just last week he uploaded a video of Bad Seed at the track! Up until now, I’ve only seen the car in the original article and in print follow-up about the article (side note: David Freiburger, of all people, was the one who pronounced the project as too dangerous).
The video takes way too much time stretching out the obvious “vette” joke, and not enough time of Magnante not getting killed, but it’s still enjoyable:
I have a Hemi… it’s an all aluminum 1789 CC DOHC, fed by mechanical fuel injection in my 1971 Alfa Spider.
I have a wedge, max rpm is 10k rpm or a little more (mind you I haven’t run it that high, only maybe 9k). 1040cc fed by twin Weber 40’s.
If the goal is a hemispherical combustion chamber, you’ve got to stop messing around with poppet valves and go two-stroke.
My Dad, as engineer, loved his SAAB 2 strokes. He liked to say that “the redline is one rpm less than the destruction point of the materials.”
Just as well my tach is broken, then.
You don’t really need it at all, until you do and then it’s too late to worry anyhow.
It got me to work today, so with any luck it’ll also get me home. That’s pretty much all I can ever reasonably ask of my vehicles.
The Hemi itself is obsolescent. The advent of four valve heads which achieve better airflow by using two smaller valves instead of one big one means the most common combustion chamber design is a pent roof which is more of a triangular prism shape.
Even the modern Chrysler “Hemi” doesn’t use a true hemispherical combustion chamber but more of a shallower “orange peel” shape like this pic of Hellcat heads which also shows the twin spark plugs for better flame propagation